472 



SCIENCE. 



[Vol. XIII. No. 33: 



pumps, and auxiliary condensers, and pumps for the auxiliary 

 machinery. The torpedo outfit for auto-mobile torpedoes, prob- 

 ably of the Howell type, will consist of six launching-tubes, — one 

 forward, another aft, and two on each broadside, — and in addi- 

 tion there will be the usual outfit of boat torpedoes. The rig is 

 that of a two-masted schooner of small sail area, steam being the 

 motive power on which the main dependence will be placed. The 

 cost of these cruisers will be $700,000 each. The bids for them 

 will be opened in August next. 



ELECTRICAL 



POWER TRANSMISSION 

 CITY, NEV. 



AT VIRGINIA 



"More power, economical power," has now for several years 

 been the imperative demand of the owners of mining properties on 



At the stamp-mill of the Nevada Mill and Mining Company, 

 water-power was obtained at the level of the mill from a reservoir 

 on the side of the mountain. The mill contains 60 stamps, with 

 their complement of pans, settlers, agitators, rock-breakers, etc. 

 The water-power readily available was entirely inadequate for the 

 operation of the mill. 



The problem was submitted to the Brush Electric Company 

 through its agents, the California Electric Light Company of San 

 Francisco. A solution was speedily offered, and the plans were 

 accepted by the owners of the Nevada Mill and ChoUar Mine. 

 The shaft of the latter is close to the stamp-mill. It was proposed 

 to collect the waste water from the surface wheel at the mill, con- 

 vey it in pipes to the shaft of the Chollar Mine, and thence down 

 the shaft until a sufficient head should be obtained to produce the 

 power required. The scheme was novel, and presented many dififi- 



THE PELTON WATER-WHEEL USED UNDER lliSO FEET HEAD IN THE CHOLLAR MINE. 



the celebrated Comstock Lode at Virginia City. The problem has 

 been to work the enormous quantities of low-grade ore at a profit. 

 Large sums have been expended in carrying water from streams in 

 the neighboring Sierra Nevada Mountains for a distance of some 

 thirty miles, to be utilized at the mines and mills on the Comstock. 

 But this supply of water is limited and variable, and by no means 

 meets the demand. Operations have frequently been suspended 

 on this account, causing great loss to the mine-owners, and hard- 

 ship to the laborers dependent upon the active working of the ores. 

 The best engineering talent of the country has been called to 

 work on this vital problem of power-supply, and new arrangements 

 have been made for increasing the amount of water ; but vast pow- 

 ers now within reasonable range are still running to waste, which 

 the use of electricity alone can conserve. 



culties. However, experts pronounced the plans feasible, and work 

 was begun last winter. 



At the 1,650-foot level of the Chollar Mine a subterranean cham- 

 ber was excavated out of solid porphyry for the reception of the 

 dynamo electric generators and water-wheels. This chamber is 

 50 feet in length by 25 feet in width, and 12 feet in height, clear 

 of all timbers. From the tank containing the waste surface water, 

 two wrought-iron pipes are led to the subterranean chamber, one 

 10 and one 8 inches in diameter. At the bottom of the shaft a Y 

 unites these two pipes into a single one 14 inches in diameter, out 

 of which six 6-inch pipes run to the nozzles of the water-wheels 

 provided to drive the large Brush dynamo electric generator. 



The underground electrical station is of the most interesting 

 character, and is shown in our illustrations. The large Brush pri- 



